[[["容易理解","easyToUnderstand","thumb-up"],["確實解決了我的問題","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["難以理解","hardToUnderstand","thumb-down"],["資訊或程式碼範例有誤","incorrectInformationOrSampleCode","thumb-down"],["缺少我需要的資訊/範例","missingTheInformationSamplesINeed","thumb-down"],["翻譯問題","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["上次更新時間:2025-09-05 (世界標準時間)。"],[[["\u003cp\u003eThe \u003ccode\u003egoogle_job_scheduler.maintenance_cpu_percentage\u003c/code\u003e flag can be adjusted to allocate between 20% and 100% of CPU cores for columnar engine maintenance tasks, with the default set at 20%.\u003c/p\u003e\n"],["\u003cp\u003eTo speed up columnar engine operations, you can increase the number of worker processes by modifying the \u003ccode\u003egoogle_job_scheduler.max_parallel_workers_per_job\u003c/code\u003e flag, which defaults to 2.\u003c/p\u003e\n"],["\u003cp\u003eThe frequency of auto-columnarization can be customized by setting the \u003ccode\u003egoogle_columnar_engine.auto_columnarization_schedule\u003c/code\u003e flag to specify how often (in hours) it should run.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003egoogle_columnar_engine.enable_auto_columnarization\u003c/code\u003e flag can be set to \u003ccode\u003eOFF\u003c/code\u003e if you prefer to manually manage the columnar engine population, instead of the default \u003ccode\u003eON\u003c/code\u003e for auto-population.\u003c/p\u003e\n"]]],[],null,["# Tune the columnar engine for AlloyDB Omni on a VM\n\nSelect a documentation version: Current (16.8.0)keyboard_arrow_down\n\n- [Current (16.8.0)](/alloydb/omni/current/docs/columnar-engine/tune-columnar-engine)\n- [16.8.0](/alloydb/omni/16.8.0/docs/columnar-engine/tune-columnar-engine)\n- [16.3.0](/alloydb/omni/16.3.0/docs/columnar-engine/tune-columnar-engine)\n- [15.12.0](/alloydb/omni/15.12.0/docs/columnar-engine/tune-columnar-engine)\n- [15.7.1](/alloydb/omni/15.7.1/docs/columnar-engine/tune-columnar-engine)\n- [15.7.0](/alloydb/omni/15.7.0/docs/columnar-engine/tune-columnar-engine)\n\n\u003cbr /\u003e\n\nThis document describes how to tune the columnar engine for an AlloyDB Omni on a VM. This document assumes that you are familiar with PostgreSQL.\n\n\u003cbr /\u003e\n\n### Adjust the CPU resources for maintenance tasks\n\nThis example configures the columnar engine to use 50% of the CPU cores. \n\n google_job_scheduler.maintenance_cpu_percentage = 50\n\nColumnar engine uses up to 20% of CPU cores for background maintenance jobs, such as population, refresh, and recommendation. To adjust the CPU resources to allow for maintenance tasks, set the `google_job_scheduler.maintenance_cpu_percentage` flag to a value from 20 to 100. The default value is 20. The lowest CPU utilization for background maintenance tasks is 1 vCPU.\n\n### Increase the speed of worker processes\n\nThis example sets four worker processes. \n\n google_job_scheduler.max_parallel_workers_per_job = 4\n\nThe columnar engine uses up to two worker processes for population and refresh background jobs. To increase the speed of these operations, set the following flag to increase the number of worker processes for background jobs. The default setting is 2 worker processes. These processes run on limited CPU resources as specified in the `google_job_scheduler.maintenance_cpu_percentage` flag. This flag does not require the database to be restarted.\n\n### Change the auto-columnarization schedule\n\nThis example sets the auto-columnarization schedule to six hours. \n\n google_columnar_engine.auto_columnarization_schedule = 'EVERY 6 HOURS'\n\nThe auto-columnarization schedule can be set in the `google_columnar_engine.auto_columnarization_schedule` flag based upon anticipated scan-heavy workloads. Specify one or more hours for this flag. Changing the value of this flag does not require a database restart.\n\n### Manually populate the columnar engine\n\nThis example lets you only manually populate the columnar engine. \n\n google_columnar_engine.enable_auto_columnarization = OFF\n\nIf you prefer to only manually populate the columnar engine, set the `google_columnar_engine.enable_auto_columnarization` flag to `OFF`. By default, the flag is set to `ON`. Changing the value of this flag does not require a database restart.\nSee [Manage Content Manually](/alloydb/omni/current/docs/columnar-engine/manage-content-manually) section for more details."]]